Question: Which is {position of head of government} of {service operator} {MiG-21} ?
Paraphrase: {Service Operator} {MiG-21} is what {position of head of government}?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q150609 wdt:P137 ?X . ?X wdt:P1313 ?answer}
Answer: Premier of the State Council of the People's Republic of China, Prime Minister of Russia, Prime Minister of Albania, Prime Minister of Azerbaijan, Prime Minister of Algeria, Prime minister of India, Chief Executive Officer of Afghanistan, President of Angola, Chairman of the Council of Ministers of the USSR